A novel structural type of conformationally fixed, mixed phosphonium-iodonium ylides based on phenoxaphosphinine

A synthetic approach to a novel type of phosphonium and mixed phosphonium-iodonium ylides containing a conformationally fixed phosphonium fragment is developed. New representatives of these families of chemical compounds based on cyclic phenoxaphosphinine were synthesized. One compound was structurally characterized by single-crystal X-ray diffraction. Based on the 1 H NMR data, one can state that phosphonium ylide exists in solution in the form of two geometric isomers even at room temperature. This is indicative of pronounced double-bond character of the bond between the ylide carbon atom and the stabilizing carbomethoxy group.